Natural Hatch - when to step in?

I found a baby in my coop this morning! It was under momma & looks healthy. The other eggs I candled still look a few days away so she is still sitting on them. When i went to go check on him/her she was off to the laying off to the side and not under momma. Is she taking her other eggs precidence over her already hatched baby. She doesn't seem aggressive towards it but I am afraid that if the new born is not under momma when the other chickens go to bed there will be an issue.

I have taken it inside for a bit and given it a bit of water and food. Should I put it back under momma or take him in and put it under a lamp until his/her brother & sisters hatch.

If there's several days difference, you might want to take care of it, and then slip it back under the mother at night when the others hatch. She'll sit for about two days waiting for all the eggs to hatch. Then she'll abandon any that don't. (It's okay for the chick to come out from under the mother - they wander around fro the start.)

What I try to do is save a couple of days' worth of fertile eggs from all the hens, and then put them under the broody at the same time. That way they all hatch the same day.